Variable speed power unit



3 Sheets-Sheet 2 I INVENTORS D n/feyTer I ea e .P/e 6/ ATTO R N EY July 4, 1939. D. HEYER ET AL VARIABLE SPEED. POWER UNIT Original Filed July 11, 1'93:

7 a0 4, w 5 9 K r E6 0 3 I fl w W 7 5 k9 Y 1 8% \2 E a, 7 7 w a a 5 6 7 9 4 77 4 2 w. (M 5 w w w a \v fi v "w 5 Q mw. a w 8 x 6 July 4, 1939. D. HEYER ET AL VARIABLE SPEED POWER mm s Sheets-Sheet 5 Original Filed July 11, 1933 S R v m w R a/ Z fl u m m wgm w M v @T. T m N H A 7 V I. l fi M I 0 3 Y B Patented July 4, 1939 UNITED STATES PATENT orr lca 2,104,318, vsmmm snap rowan. um'r Don Beyer and George '1. Piieger, Los Angelea, ali!., aslignon to U. 8. Electrical Motors, Inc., a corporation of California Application July 11, 1933, Serial No. 679,896 Renewed June 13, 1938 15 Claims. (01. 74-286) I This invention relates to a power unit that is It has been proposed to vary the delivered speed of such motors over a considerable continuous 16 range, as by variable pulley structures having variable effective diameters: A system of this.

characteris described and claimed in my co- I pending application, Serial No. 667,387, entitled Variable speed electric motor drive", and filed- 20 April 22, 1933.

In that application, there is described a variable speed drive comprising a driving and a driven pulley-connected by a flexible V-belt, the driving pulley being mounted on the shaft of the motor.

5 One of the two pulleys. has a variable eflective diameter in order to vary the speed of the driven pulley. The variable pulley structure, to effect this result, includes a pair of relatively axially movable sections having opposed inclined or 30 conical faces, adapted respectively to engage opposite sides of the V-belt. When the faces are separated, the belt is allowedto move inwardly toward the axis, and the effective diameter is reduced. Conversely, when the faces are brought I 35 closer together, the belt rides radially outwardly from the axis, and the effective diameter is 50 practical for all kinds of loads. For example,

the speed ofa printing press drive must be capable of varying from a high speed down to a very slow speed, corresponding to make-up speed and operating speed. The present inven- 55 tion makes it possible to secure thiswide'range of speeds while the motor is fully energized and operatlvely connected to the load. It is, accordingly, another object of the invention to 1 provide a variable speed drive of this character in which a variable pulley structure is 6 utilized as an element in the drive. I

The wide speed variation is secured by a provision of a mechanism which is capable of subtracting speeds; one speed can be a constant one such as that of the motor, and the other, a varial0 able speed such as that obtained by a variable pulley structure operated by the motor.

This invention possesses many other advantages, and has other objectswhich may be made more easily apparent from, a consideration of several embodiments of the invention. For this purpose there are shown a few forms in the drawings accompanying and'forming part of the present specification. These forms shall now be described in detail, which illustrate the general principles of the invention; but'it is to be understoodthat this detailed description is not to be taken in a limiting sense, since the scope of the invention is best defined by the appended claims.

Referring to the drawings: Fig re 1 is a view, mainly in horizontal section,

' of one embodiment of the invention; and

Figs. 2\ and 3 are views similar to Fig. 1, but of modified forms of the-invention.

In Fig, 1 there is shown a casing 1 within which a substantially all of the variable speed mechanism can .be housed. A source of power, such as the electric motor .2 is shown as supported by a flange 3 on the wall of the casing. I, so that its shaft 4 extends substantially across the casing I.

The arrangement is such that a driven shaft 5 extends out of a casing l to be coupled in any appropriate way to a load such as a printing press or the like. This load may be of such character as to require a gradual acceleration'from stand- 40 still. By the aid of the transmission mechanism now to be described-this result can be effected, although the motor 2 may be running at full speed at all times.

Thus a .difierential mechanism 6 is supported between the walls 1 and 8 of the casing i. This differential mechanism is arranged to driveshaft 5 at a speed which is a combination of two speeds.

One of these two speeds is derived from shaft 4 by a constant ratio motion transmission mechaslon mechanism, the desired wide range of variation in the speed of the load shaft 5 can be, obtained.

The constant ratio speed transmission mechanism, shown in this instance as having a ratio of l to 1, includes a grooved pulley 9 rigidly fastened to the motor shaft 4, as by the aid of the key Ill and set screw II. This grooved pulley 9 is in driving relationship with a similar grooved pulley I2, mounted on a shaft I3. The driving relation is secured by the aid of a flexible V-belt I 4,v accommodated in the grooved faces of the pulley structures 9 and I2.

Pulley structure I2 is rigidly fastened to the shaft I3, as by the aid of the key I6 and set screw I 6. This shaft is mounted for rotation at one end in appropriate ball bearings in the wall of the casing' I. It is further supported as by ball bearing structures I1 and I9 inside of a sleeve I9, as well as by the ball bearing structure 20 inside of a driven gear member 2i fastened to the driven shaft 5.

This constant ratio transmission mechanism carries the planetary elements of one type of differential gearing. These planetary elements include a pair of sets of gears 22 and 23. Each set of gears includes a shaft 24 spaced parallel from the axis of shaft I 3 and mounted for free rotation in a spider 25. Rigidly connected to the opposite ends of shafts 24 are-the spur gears 26 and 21. Spur gear 26 is shown as smaller in size than spur gear 21. Both spur gears 26 mesh with a spur gear 28 which is coaxial with the shaft I3, and which is driven at a variable speed. In order to effect this result, gear 28 is firmly keyed to the sleeve I 9. The sleeve I9 is supported not only rotatably on the shaft I3 as by the ball bearing structures I1 and I8, but is also supported by ball bearing structure 29 in the wall 3 of the -on sleeve I8, and a similar variable diameter pulley structure 3| mounted upon the shaft 4. These two pulley structures are connected together by a flexible V-belt 32.

The variable pulley structure 3| includes a pair of relatively axially'movable pulley sections 33 and 34, having opposed inclined faces. It is apfixed on shaft 4 as by the aid of key II and the set screw 35. The section 33, however, is axially adjustable as by having an elongated hub 36,

which-is splined on key III. This hub 36 is supported as by the aid of the thrust'ball bearing structure 31 inside of an axially adjustable cup 38. The inner race of the ball bearing structure 31 is rigidly fastened to the hub 36, and the outer race is fastened to the inside of the cup".

Cup 38 is guided for axial motion inside of a. tubular extension 39 for the casing I, and is re- ..strained against angular motion therein. It is axially moved as by the aid of a threaded stud 46, journalled in a journal bearing in member '39,

and adapted to be mechanically rotated as by the I tion 43. For this purpose section 42 is indicated in the present instance as formed integral with the sleeve I9; and section at is shown as having a hub 44 splined to the sleeve i9. A compression spring 45 urges the section it toward section 632 at all times.

When the hand wheel ti is rotated to increase the effective diameter of pulley structure til, it is apparent that the belt 32 will act as a wedge between the sections 62 and 53, and will spread them apart against the resilient force exerted by the spring 45. The net result is that as the effective diameter of structure 36 increases the effective diameter of structure 36 automatically decreases. The ratio of transmission thus secured is thereby increased, the speed of rotation of sleeve I9 being greaterthan before this adjustment. Similarly, movement of wheel ti to reduce the. effective diameter of structure it will cause the belt 32 to be slackened between the sections 42 and 43, and this slack is taken up by expansion of spring d5- In this way a reduction of the pulley diameter of structure 36 results automatically in an increase in the effective pulley diameter of structure 30, and the ratio of transmission is reduced.

In the present instancethe ratio can vary approximately from about 1 to 1 to about 1 to 2 or 3.

It is thus apparent, as so far described, that the planetary gear sets 22 and 23 are rotated at a fixed speed, depending solely upon the speed of motor 2; and that the speed of the gear 28 is variable between rather wide limits. Since motor 2 is usually an alternating current induction motor type, the planetaries 22 audit! are revolved in their planetary course at a substantially constant speed.

The load shaft 5 is rigidly connected to the member 2 I, and is journalled as by'the aid of the ball bearings 46 in the wall l of easing i, as well as by the ball bearings 20 inserted between the member 2I and shaft I9. -The member it carries a spur gear- 61 which meshes with the planetary gears 27. Since planetary gears 27! are larger in diameter tharrplanetary gears 23,

it is apparent that gear 21'must be correspondingly smaller than the gear 28. It can be demonstrated that if there is a sufficient difierence between the ratio of gear 28 to gear 26, and the ratio of gear 41 to gear 2'5 it is possible, by sufficiently reducing the diameter of variable pulley structure 39, to reduce the peed of gear iii to zero. Thus, during continual rotation of shaft I3, it is possible to bring the ultimate load speedto zero by reducing the diameter of pulley struc ture 3|. 6

It is furthermore apparent that gear ii? is driven at a speed which is a combination of the speed of rotation of gear 28 and the speed of rotation of spider 25; and that the gear d? is in driving relation with the other elements of the structure through the intermediary of the planetary gears 26 and 2i.

more, journalled as by the ball bearings 88 in en the diameter of variable pulley structure 3i is adjusted to be the same as that of the invariable pulley 9, the arrangement is such that the speed of the driven shaft 5 is the same as the speed of shaft it. It is noted that these speed variations are effective without the necessity of crossed belts, pulleys l2 and 30 being continually rotated in a common direction. Furthermore, should there be a suflicient reduction possible in the efiective diameter of pulley structure 3!, it is possible actually to reverse the direction of shaft 5.

In the form of the invention shown in Fig. 2, a slightly different type of differential mechanism is illustrated. In this form the casing 48 supports, as before, an electric motor]! having a shaft 50. This shaft 56 carries a grooved pulley 5| of fixed diameter as well as a variable pulley structure 52. The pulley structure 5| forms with the corresponding pulley structure 53 a fixed ratio I ture .52 will now be described. Section SI of this pulley structure is fixed to the hollow extension 62 of shaft 50, as by a set screw 63. The

axially adjustable section has a hub 65 through which passes a dlametric pin 66. This pin 66 is fastened to a shaft 51 telescoping in the hollow portion 82. The hollow portion 52 has slots 68 permitting axial adjustment of shaft 61'. It is,

furthermore, apparent that pin '66 in conjunction with slots 58 form a driving connection between shaft 50 and section t l;

Shaft 61 is axially adjustable to move section 84 toward and from section 6|. For this purpose this shaft is rotatably' mounted in a cup til by the aid of the ball thrust bearings 10.

Cup Gil-is axially slidable in the hollow extension II cfgcasin'g 48, but the hub is restrained against angular motion. Hand wheel 12 fastened to the threaded stud I3 is utilized for moving the cup 29 axially in a manner entirely similar tothe' mechanism shown in Fig. l. i

The corresponding adjustable pulley structure 55 is mounted on a shaft l t. Section of structure 55 is axially fixed on shaft M as by the aid of a lrey l6 and set screw ll. The corresponding section it has an elongated hub it which' is axially slidable on shaft id as by the aid of splines.- In order to slide the section ill axially, hub "is is journalled in a cup til as by the aid of the ball 7 thrust bearings iii. The cup tilt is slidable inside of cylindrical casing 82, and is restrained against angular rotation therein. A compression spring resiliently urges the cup tit downwardly so as to tend to bring the sections it and '18 together.

Shaft id is further rotatably supported as by the aid, of the ball bearing structure'td inside of the member (85. ,Tnls member 8%: is shown as'connested rigidly to the driven shaft til.

The constant ratio transmission mechanism serves to rotate a, sleeve it surrounding the shaft i 3. This sleeve is joined by the aid of the ball bearings [ill on the shaft it. It is, furtherwall 58.

Sleeve 85 is shown as integrally joined to a spur gear 89 having an axis coaxial with the sleeve 86 and located in chamber 51. Similarly, shaft 14 rotates a spider Qt which is keyed to the shaft 14 and is journalled in the appropriate contiguous parts between ball bearings 9!, 92. The

spider 90 carries a plurality of shafts t3 spaced from the axis of the shaft 714. Upon these shafts 93 are mounted for free rotation the planetary gears 95. These planetary gears are thus revolved in their planetary course by shaft l5. They are, furthermore, in meshwith the gear 89, and are also inmesh with the internal gear 95 shown as integral with the member 85. It is thus seen that the internal gear as is the driven gear since it isrigidly and permanently fastened to the driven shaft M.

It is also seen that the planetary gears 93 are driven at a variable speed, and that the spur gear 89 is driven at a constant "speed. Both of these speeds are in thesame direction. However, the resultant speed of rotation of driven gear 95 is a combination of these two speeds. It can be shown that if the ratio of transmission between pulley structures 52 and 55 be small enough, the resultant speed of gear $5 can be brought to zero, and in fact can be reversed. The required reduction in the ratio of transmissome extent upon the diameters of the planetary gears 94. I

As in .the first form described, it is apparent that the driven gear 951s in driving relation with the constant ratio mechanism'and the variable ratio mechanism.

The mode of adjusting the variable speed transmission mechanism is substantially the same-as in the first form described. The diameter of,

pulleystructure 55 is automatically adjusted in response to the variation in the efiective pulley diameter of pulley structure 52.

In the forms so far described the gear elements I making up the difierential mechanism are spur gears. In the form shown in Fig. 3, a bevel gear differential mechanism is disclosed. In this form there is a casing 95, on one wall of which is supported the electric motor Q1. The shaft 98 of the electric motor 91 is journalled as by the aid of a ball bearing structure ii? in the wall it!) of the mission mechanisrn. Thus, for example, bevel.

gear its can be rotatably mounted upon shaft its as by the ball bearing structures Ht. Fastened over the hub of bevel gear tilt is a spur gear ill driven at a constant speed as by the aid of the gear 952' fastened to the shaft 98. It is apparent that bevel gear its is thus driven through a constant ratio motion transmitting mechanism. I

Meshing with both of the bevel gears its and its, are a pair of planetary gears i it and ti l.

iii)

These planetary bevel gears are mounted for to 30 sion by the variable pulley structure depends to rotation on the radial spokes H5, H5 of a spider Ill. The spider III is mounted as by the aid of ball bearings for free rotation upon shaft I03. Rotation of spider H1 is obtained by the aid of a variable transmission mechanism. This includes the spur gear I I8 extending concentrically around the spider I I1 and appropriately fastened thereto for driving relation therewith. Gear II8 can be made in split halves, so as to facilitate assembly with respect to the spider II1. This gear H8 is, furthermore, driven by a gear II9 mounted on a shaft I which is driven through a variable ratio transmission mechanism. This shaft I20 is appropriately journalled in the walls of casing 95.

The variable ratio mechanism comprises the variable pulley structure I2I mounted on the motor shaft 98,/and a corresponding variable pulley structure I22 mounted on shaft I20. These two pulley structures are connected as by a flexible belt I23.

The pulley section I24 of structure I2I is fixed against axial movement. The corresponding section I25, however, is axially movable with respect to section I24. A pin I26 passes through the hub of section I25, and also passes through slots I2'I in the .hollow portion of shaft 98. The

pin I26 passes through a thrust rod I28 accom modated inside of the hollow portion of shaft 98. It is apparent that by pushing rod I28 upwardly the effective pulley diameter is increased. The thrust rod I20 is adapted to be moved axially as by the aid of a screw I29 threaded into an aperture in the bracket I30. The inner end ofscrew I29 abuts against the lower end of thrust rod I28. This screw I29 can be manually, rotated as by the hand wheel I3I. When the effective diameter of structure I2I is increased by turning screw I29 into the hollow portion of shaft 98, the corresponding pulley structure I22 has its effective diameter automatically reduced. In order to accomplish this result, pulley structure I22 includes a section I32 fixed upon shaft I20. The corresponding section I33 is axially movable as by being splined to shaft I20. A compression spring I34 exerts a resilient force always tending to bring the sections I32 and I33 together.

As the effective diameter of pulley I2I is positively increased by the aid of the thrust rod I20 the belt I23 wedges the sections I32 and I33 apart, and the effective diameter of pulley structure I22 is decreased. However, upon retraction of the screw I29, compression spring I34 is permitted to expand to take up the resultant belt slack, and section I25 is urged downwardly, causing a reduction in the effective diameter of pulley structure I2I.

It can be shown that, when gears -I II and H8 are rotated at the same speed, the driven or load shaft I03 rotates at the same speed. However, this condition exists when the effective diameter of pulley structure I2I is a maximum. Now as the effective diameter of this pulley structure is reduced, the speed of gear H8 is correspondingly reduced, and upon a sufficient reduction the shaft I03 can be caused to stand still. Further reduction beyond this point would cause a reversal in the direction of rotation of shaft In this case also it is apparent that the driven more, apparent that the speed of shaft I03 is a combination of the speeds of motor shaft 90 and of shaft I20. By the aid of the differential mechanism it is thus apparent that the load shaft has a wider speed variation than could possibly be obtained by a mere variation in effective pulley diameters. As pointed out heretofore, this is highly desirable for driving certain kinds of loads such as printing presses, which require a gradual bringing of the load up to a maximum speed from zero. The mechanisms described are well adapted to perform this function.

We claim:

1. In an enclosed electrically driven variable speed power unit, a planetary gear mechanism having two actuating members and a driven member, means forming a constant ratio power transmission'actively engaging one of said actuating members ofthe planetary gear mechanism, means forming a variable ratio power transmission actively engaging the other of said actuating members ofthe planetary gear mechanism, a casing having walls enclosing, and

means supporting, said planetary gear mechanism and the associated power transmissions; a load driving means engaged by said driven member of the planetary gear mechanism and projecting outside of said casing, a driving shaft [or operating said power transmissions, an electric motor in axial driving relation to said driving shaft, and means supporting said electric motor by one wall of said casing.

2. The construction as set forth in claim 1; in which said constant ratio power transmission includes a driving means and a driven means, one of said means being secured to said driving shaft; and in which said variable ratio power transmission includes a pair of adjustable pulley structures, each of said pulley structures including a pairof pulley sections having opposed inclined' belt engaging faces forming by relative axial adjustment variable effective pulley diameters a belt in active driving relation to said pulley structures and ratio adjusting means for adjusting the relative axial position of at least the pulley sections forming one of said pulley structures. v

3. The construction as set forth in claim 1; in which said constant ratio power transmission includes two constant diameter pulleys and a flexible'transmission means engaging said pulleys, one of said pulleys being secured to said driving shaft and the other of said pulleys engaging said planetary gear mechanism; and in which said variable ratio power transmission includes a pair of adjustable pulley structures each of said pulley structures including a pair of pulley sections having opposed inclined belt engiging faces forming by relative axial adjustment variable effective pulley diameters, a belt in active driving relation to said pulley structures, one of said pulleystructures being secured to said driving shaft and the other of said pulley structures engaging said planetary gear mechanism, and" ratio adjusting means for adjusting member, said actuating members and said driven members being relatively rotatable about a common axis, a shaft rotatably supported coaxial with said planetary gear mechanism and engaging one of said actuating members of said planetary gear mechanism, a tubular shaft rotatably mounted coaxial with said first mentioned shaft,

said tubular shaft engaging the other of said in power transmission relation to said first menfirst mentioned adjustable diameter tioned constant diameter pulley, a second ad-- Justable diameter pulley secured to said driving shaft and in powert'ransmission relation to said pulley,

means for adjusting the relative axial position of at least the pulley sections forming one of said adjustable diameter pulleys, a casing having walls enclosing, and means supporting, said plan-v etary gear mechanism and said pulley transmissions, a load driving means engaged by said driven member of the planetary gear mechanism and projecting outside of said casing, an electric motor in axial driving relation to said driving shaft, and means supporting said electric motor by one wallof said casing.

.6.-The construction as set forth in claim 5,

in which said casing includes anauxiliary gear case housing said planetary gear mechanism.

7. The construction as set'forth in claim 5, in

, which said means supporting said motor includes an aperture formed in the wall of said casing ad- 1 jacent said motor, whereby said motor projects intosaid casing beyond the wall of said casing adjacent said aperture.

8. In an enclosedelectrically driven variable speed power unit; a' planetary gear mechanism including an internal gear member, a load shaft coaxial therewith and connected thereto, a gear member having external teeth and of smaller diameter, than the load gear member, and a planetary gear member interposed between the said other gear members; a pair of shafts coaxial with said load shaft, one of said pair of shafts being tubular and rotatably supported on the other of said pair of shafts, one. of said pair of shafts engaging said external gear and the other of said pair of shafts engaging said planetary gear member; adriving shaft, a constant ratio power transmission having one pulley secured to I said driving shaft and a second pulley secured to one of said pair of shafts, a variable ratio gear member.

10. The combination r claim 8, in which each of the adjustable diameter pulleys oi the variable ratio transmission includes an axially .means means, an electric motor in axial driving relation fixed pulley section and an axially adjustable pulley section, said pulley sections having op-' posed inclined belt engaging faces forming by relative axial adjustment variable effective pulley diameters, the fixed pulley section of one pulley structure being oppositely faced to the similar pulley section of the other pulley structure, and in which the variation in ratio is obtained by the relative, axial adjustment of at least the pulley sections forming one of said pulley structures.

11. The combination of claim 8, in which said casing includes an auxiliary gear case housing said planetary gear mechanism.

12., In an enclosed-electrically driven variable speed power unit, a driving shaft, a loaddriving means, means for transmitting power at a varible speed ratio from said driving shaft to said load driving means, said power transmitting means includinga driving pulley structure a driven pulley structure anda belt in active driving relation to said pulley structure, at least one of said pulley structures having an adjustable effective diameter, a casing having walls enclosing, and supporting, said power transmitting to said driving shaft, and means for supporting said electric motor by one wall of said casing, said means for supporting said motor including an aperture formed in the wall of said casing adjacent said motor, whereby said motor projects into said casing beyond the wall of said casing adjacent said motor. 4 13. In an enclosed electrically driven variable speed power unit, a driving shaft, a load driving means, means fortransmitting power at a variable speed from said driving shaft to said load driving means, said power transmitting means including a drivingpulley structure, a driven pulley structure, and a bet in active driving relation to said pulley structures, at least one of said pulley structures having an adjustable effective diameter, a casing having walls enclosing and means supporting, said power transmitting means, an electric motor in driving relation to said driving shaft, and means for supporting said electric motor by one wall of said casing.

114. In a variable speed drive, a planetary gear mechanism having two actuating members and a driven member, said actuating members and said driven member being relatively rotatable about a common axis, a shaft rotatably supported coaxial with said'plan'etary gear mechanism and engaging one of said actuating members of said planetary gear mechanism, a tubular shaft rotatably mounted coaxial with said first mentioned shaft, said tubular shaft engaging the other of said actuating members of said planetary gear mechanism, an adjustable pulley structure shaft and inpo wer transmission relation to said first mentioned constant diameter pulley, a second adjustable diameter pulley secured to said driving shaft and in power transmission relation to said first mentioned adjustable diameter pulley, means for adjusting the relative axial position of at least thepulley sections forming one of said adjustable diameter pulleys, and a load driving means engaged by said driven member of the planetary gear mechanism.

15. In an electrically driven enclosed variable speed power unit, a driving shaft, a load driving shaft, means for transmitting power at an adjustable speed ratio from said driving shaft to said load driving shaft, said power transmitting means including a pair of pulley structures, a belt in active driving relation to said pulley structures, one of said pulley structures being sup.- ported on said driving shaft and having an adjustable efiective diameter, a casing having w enclosing, and means supporting, said .power transmitting means, an electric motor in axial driving relation to said driving shaft, means for supporting said electric motor by one wall of said casing, and means supported on the wall of said casing opposite said motor and adjacent said driving shaft for adjusting the efiective diameter of said adjustable pulley structure.

DON HEYER.

GEORGE T. PFLEGER. 

